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<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        //格式
        function 函数名() {
            return 需要返回的结果;
        }
        函数名();
        //代码验证
        function sum(aru) {
            return (aru);
        }

        console.log(sum('大肘子'));
    </script>
</head>

<body>

</body>

</html>